Erik
Thanks for that info. (now comes he "however") However, Hawaii is in the Northern Hemisphere and Gardner is in the Southern Hemispere Hawaii is about 2000 miles North of Gardner and I wonder how they got thru the North Equatorial Counter-Current and the South Equatorial Counter Current both of which flow from West to East (that's why they are called "Counter-Currents")??
And how do they get through the
SOUTH-east trade winds that exist south of the counter-current in August? These winds from the south-east blow towards the NORTH-west and the north blowing component would keep a raft from drifting further south for the necessary 600 nautical miles to get to Gardner.
Your example of a six foot man drowning in a river with a five foot average depth, while humorous, is not relevant for several reasons. First, it depends on how fine grained the average is. If the average depth of the river for its entire length is five feet then for that one spot it did not provide a reasonable estimate of the depth that the guy would encounter. But if there was a chart of the average depth broken up into one foot squares then he would have seen the eight foot hole in the average listed for that spot. The pilot charts break the ocean up into 5 degree squares (300 NM on a side) and also in to 12, one month periods, per year so the accuracy of the prediction for each square and month is of a much higher accuracy than in your humorous example.
If your guy jumped into the river 30 or 40 times it is highly unlikely that he would land in that 8 foot deep hole more than once and he would encounter depths on each jump close to the average 5 foot depth most of the time especially as he was moving down the shoreline between each leap just as the life raft would be doing in the open ocean. You're right, if you have actual measured weather data for the period then your use that to predict the drift, do you have that data for Doran? If you don't have that data then you must use the best available data and that is contained in the pilot chart. I have already said that on any particular day that the average trade wind might not be present, it might be the
one day out of a hundred when the wind is out of the south-west, or on the second day or even the third. But for a 30 or 40 day period we can be very sure that the winds encountered were much closer to the winds depicted on the pilot chart than to the outlier south-west wind.
gl